L. Schjøth, J. Frisvad, Kenny Erleben, J. Sporring
A number of popular global illumination algorithms uses density estimation to approximate indirect illumination. The density estimate is performed on finite points -- particles -- generated by a stochastic sampling of the scene. In the course of the sampling, particles, representing light, are stochastically emitted from the light sources and reflected around the scene. The sampling induces noise, which in turn is handled by the density estimate during the illumination reconstruction. Unfortunately, this noise reduction imposes a systematic error (bias), which is seen as a blurring of prominent illumination features. This is often not desirable as these may lose clarity or vanish altogether. We present an accurate method for reconstruction of indirect illumination with photon mapping. Instead of reconstructing illumination using classic density estimation on finite points, we use the correlation of light footprints, created by using Ray Differentials during the light pass. This procedure gives a high illumination accuracy, improving the trade-off between bias and variance considerable as compared to traditional particle tracing algorithms. In this way we preserve structures in indirect illumination.
{"title":"Photon differentials","authors":"L. Schjøth, J. Frisvad, Kenny Erleben, J. Sporring","doi":"10.1145/1321261.1321293","DOIUrl":"https://doi.org/10.1145/1321261.1321293","url":null,"abstract":"A number of popular global illumination algorithms uses density estimation to approximate indirect illumination. The density estimate is performed on finite points -- particles -- generated by a stochastic sampling of the scene. In the course of the sampling, particles, representing light, are stochastically emitted from the light sources and reflected around the scene. The sampling induces noise, which in turn is handled by the density estimate during the illumination reconstruction. Unfortunately, this noise reduction imposes a systematic error (bias), which is seen as a blurring of prominent illumination features. This is often not desirable as these may lose clarity or vanish altogether.\u0000 We present an accurate method for reconstruction of indirect illumination with photon mapping. Instead of reconstructing illumination using classic density estimation on finite points, we use the correlation of light footprints, created by using Ray Differentials during the light pass. This procedure gives a high illumination accuracy, improving the trade-off between bias and variance considerable as compared to traditional particle tracing algorithms. In this way we preserve structures in indirect illumination.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130808250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Przemyslaw Musialski, R. Tobler, S. Maierhofer, C. A. Wüthrich
Subdivision surfaces are methods for creating smooth surfaces out of coarse polyhedral meshes. Due to their recursive nature they are ideally suited for adding geometric detail on different resolutions. When modeling real-world surfaces it is possible to extract the fine surface details from a material and apply these on dense meshes in the form of vertex displacements. Material characteristics are a mixture of features at different scales, which can be recovered by a frequency decomposition of an input height map. Applying these sub-bands as displacement in a recursive multiresolution fashion allows the ability to influence or mix details obtained from one or more sources. This paper presents a method for computing multiresolution displaced subdivision surfaces on the GPU that performs in real-time and provides an interactive control over the obtained results.
{"title":"Multiresolution geometric details on subdivision surfaces","authors":"Przemyslaw Musialski, R. Tobler, S. Maierhofer, C. A. Wüthrich","doi":"10.1145/1321261.1321299","DOIUrl":"https://doi.org/10.1145/1321261.1321299","url":null,"abstract":"Subdivision surfaces are methods for creating smooth surfaces out of coarse polyhedral meshes. Due to their recursive nature they are ideally suited for adding geometric detail on different resolutions. When modeling real-world surfaces it is possible to extract the fine surface details from a material and apply these on dense meshes in the form of vertex displacements. Material characteristics are a mixture of features at different scales, which can be recovered by a frequency decomposition of an input height map. Applying these sub-bands as displacement in a recursive multiresolution fashion allows the ability to influence or mix details obtained from one or more sources.\u0000 This paper presents a method for computing multiresolution displaced subdivision surfaces on the GPU that performs in real-time and provides an interactive control over the obtained results.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128125415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we propose a novel approach towards parametrically controlled artificial terrain generation. Our proposed method focuses on generation of terrains having mountains of prespecified height and spread of base region and peak nearly at a prespecified location. Means of performing advanced tuning on the terrain to produce unusual artifacts on the terrain is also demonstrated and how our algorithm performs better in comparison with the well known terrain generation algorithms when used to solve the same problem is observed.
{"title":"Parametrically controlled terrain generation","authors":"K. R. Kamal, Mohammad Yusuf Sarwar Uddin","doi":"10.1145/1321261.1321264","DOIUrl":"https://doi.org/10.1145/1321261.1321264","url":null,"abstract":"In this paper, we propose a novel approach towards parametrically controlled artificial terrain generation. Our proposed method focuses on generation of terrains having mountains of prespecified height and spread of base region and peak nearly at a prespecified location. Means of performing advanced tuning on the terrain to produce unusual artifacts on the terrain is also demonstrated and how our algorithm performs better in comparison with the well known terrain generation algorithms when used to solve the same problem is observed.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126081673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Hengel, A. Dick, Thorsten Thormählen, Ben Ward, P. Torr
This paper describes an interactive method for generating a model of a scene from image data. The method uses the camera parameters and point cloud typically generated by structure-and-motion estimation as a starting point for developing a higher level model, in which the scene is represented as a set of parameterised shapes. Classes of shapes are represented in a hierarchy which defines their properties but also the method by which they are localised in the scene, using a combination of user interaction, sampling and optimisation. Relations between shapes, such as adjancency and alignment, are also specified interactively. The method thus provides a modelling process which requires the user to provide only high level scene information, the remaining detail being provided through geometric analysis of the image set. This mixture of guided, yet automated, fitting techniques allows a non-expert user to rapidly and intuitively create a visually convincing 3D model of a real world scene from an image set.
{"title":"A shape hierarchy for 3D modelling from video","authors":"A. Hengel, A. Dick, Thorsten Thormählen, Ben Ward, P. Torr","doi":"10.1145/1321261.1321273","DOIUrl":"https://doi.org/10.1145/1321261.1321273","url":null,"abstract":"This paper describes an interactive method for generating a model of a scene from image data. The method uses the camera parameters and point cloud typically generated by structure-and-motion estimation as a starting point for developing a higher level model, in which the scene is represented as a set of parameterised shapes. Classes of shapes are represented in a hierarchy which defines their properties but also the method by which they are localised in the scene, using a combination of user interaction, sampling and optimisation. Relations between shapes, such as adjancency and alignment, are also specified interactively. The method thus provides a modelling process which requires the user to provide only high level scene information, the remaining detail being provided through geometric analysis of the image set. This mixture of guided, yet automated, fitting techniques allows a non-expert user to rapidly and intuitively create a visually convincing 3D model of a real world scene from an image set.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127156398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
At the moment the noise functions available in a graphics programmer's toolbox are either slow to compute or they involve grid-line artifacts making them of lower quality. In this paper we present a real-time noise computation with no grid-line artifacts or other regularity problems. In other words, we put a new tool in the box that computes fast high-quality noise. In addition to being free of artifacts, the noise we present does not rely on tabulated data (everything is computed on the fly) and it is easy to adjust quality vs. quantity for the noise. The noise is based on point rendering (like spot noise), but it extends to more than two dimensions. The fact that it is based on point rendering makes art direction of the noise much easier.
{"title":"Fast high-quality noise","authors":"J. Frisvad, G. Wyvill","doi":"10.1145/1321261.1321305","DOIUrl":"https://doi.org/10.1145/1321261.1321305","url":null,"abstract":"At the moment the noise functions available in a graphics programmer's toolbox are either slow to compute or they involve grid-line artifacts making them of lower quality. In this paper we present a real-time noise computation with no grid-line artifacts or other regularity problems. In other words, we put a new tool in the box that computes fast high-quality noise. In addition to being free of artifacts, the noise we present does not rely on tabulated data (everything is computed on the fly) and it is easy to adjust quality vs. quantity for the noise. The noise is based on point rendering (like spot noise), but it extends to more than two dimensions. The fact that it is based on point rendering makes art direction of the noise much easier.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131761966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We revisit the assumptions behind traditional image compositing techniques. By analysing the process we separate the colour operations from those for coverage and show that this usefully leads to a more general compositing equation than previously used. We then examine the colour operations in more detail and show how new operations can easily be incorporated in a standard compositor. Practical examples show the new approach and reveal some beneficial effects, not previously achievable within a compositor.
{"title":"Generalised compositing","authors":"P. Willis","doi":"10.1145/1321261.1321284","DOIUrl":"https://doi.org/10.1145/1321261.1321284","url":null,"abstract":"We revisit the assumptions behind traditional image compositing techniques. By analysing the process we separate the colour operations from those for coverage and show that this usefully leads to a more general compositing equation than previously used. We then examine the colour operations in more detail and show how new operations can easily be incorporated in a standard compositor. Practical examples show the new approach and reveal some beneficial effects, not previously achievable within a compositor.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121430347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For wireless network based graphics applications, a key challenge is how to efficiently transmit complex 3D models over bandwidth-limited wireless channels. Recently, several view-dependent 3D progressive mesh transmission schemes have been proposed, which save the transmission bandwidth through only delivering the visible portions of a mesh model. In this paper, we propose to incorporate the illumination effects into the existing view-depend progressive mesh transmission system to further improve the performance. In particular, we propose a novel distortion model, which consists of both illumination distortion and geometry distortion. We further simplify the distortion model in order to compute the rate-distortion function for each segment of a mesh model in a fast manner. Based on our proposed simplified distortion model, given the viewing and lighting parameters, we are able to optimally allocate bits among different segments in real time. Experimental results show that significant quality improvement can be achieved by taking into account the illumination effects.
{"title":"Illumination and view dependent progressive transmission of semi-regular meshes with subdivision connectivity","authors":"Wei Guan, Juyong Zhang, Jianfei Cai, Jianmin Zheng","doi":"10.1145/1321261.1321300","DOIUrl":"https://doi.org/10.1145/1321261.1321300","url":null,"abstract":"For wireless network based graphics applications, a key challenge is how to efficiently transmit complex 3D models over bandwidth-limited wireless channels. Recently, several view-dependent 3D progressive mesh transmission schemes have been proposed, which save the transmission bandwidth through only delivering the visible portions of a mesh model. In this paper, we propose to incorporate the illumination effects into the existing view-depend progressive mesh transmission system to further improve the performance. In particular, we propose a novel distortion model, which consists of both illumination distortion and geometry distortion. We further simplify the distortion model in order to compute the rate-distortion function for each segment of a mesh model in a fast manner. Based on our proposed simplified distortion model, given the viewing and lighting parameters, we are able to optimally allocate bits among different segments in real time. Experimental results show that significant quality improvement can be achieved by taking into account the illumination effects.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128693677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we present a novel user interface design for mobile games using its built-in camera. It is motivated by the problem of limited number of keys on the small keypad of mobile devices. We implement two different ways, with and without the use of markers, to study the effectiveness of the design in a 2-dimensional and 3-dimensional game respectively. The algorithms implemented in the design are lightweight enough so that they are executable in real-time and at the same time, able to produce realism for the games.
{"title":"Design and implementation of a built-in camera based user interface for mobile games","authors":"Khoa Nguyen Tran, Zhiyong Huang","doi":"10.1145/1321261.1321266","DOIUrl":"https://doi.org/10.1145/1321261.1321266","url":null,"abstract":"In this paper, we present a novel user interface design for mobile games using its built-in camera. It is motivated by the problem of limited number of keys on the small keypad of mobile devices. We implement two different ways, with and without the use of markers, to study the effectiveness of the design in a 2-dimensional and 3-dimensional game respectively. The algorithms implemented in the design are lightweight enough so that they are executable in real-time and at the same time, able to produce realism for the games.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124341937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Nowrouzezahrai, P. Simari, E. Kalogerakis, E. Fiume
We present a method for creating a geometry-dependent basis for diffuse precomputed radiance transfer. Unlike previous PRT bases, ours is derived from Principal Component Analysis of the sampled transport functions at each vertex, without relying on pre-projections to secondary bases, such as the Spherical Harmonics or Haar wavelets. It allows for efficient evaluation of shading, has low memory requirements and produces accurate results with few coefficients. We are able to capture all-frequency effects from both distant and near-field dynamic lighting in real-time and present a simple and efficient rotation scheme. Reconstruction of the final shading becomes a low-order dot product and is performed on the GPU.
{"title":"Eigentransport for efficient and accurate all-frequency relighting","authors":"D. Nowrouzezahrai, P. Simari, E. Kalogerakis, E. Fiume","doi":"10.1145/1321261.1321290","DOIUrl":"https://doi.org/10.1145/1321261.1321290","url":null,"abstract":"We present a method for creating a geometry-dependent basis for diffuse precomputed radiance transfer. Unlike previous PRT bases, ours is derived from Principal Component Analysis of the sampled transport functions at each vertex, without relying on pre-projections to secondary bases, such as the Spherical Harmonics or Haar wavelets. It allows for efficient evaluation of shading, has low memory requirements and produces accurate results with few coefficients. We are able to capture all-frequency effects from both distant and near-field dynamic lighting in real-time and present a simple and efficient rotation scheme. Reconstruction of the final shading becomes a low-order dot product and is performed on the GPU.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120916698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A motion trend analysis method is proposed to reconstruct human motion from un-calibrated monocular video. In this paper, relocation of human subject is the main concern, which is one of the most difficult parts in motion reconstruction and critically affects the accuracy of human posture generation. Numerical studies are conducted on experiments from synthetic and real video data to demonstrate the correctness of the recovered human translation in the proposed system.
{"title":"Monocular reconstruction of human translation in motion sequence by MTA","authors":"Li Zhang, Ling Li","doi":"10.1145/1321261.1321275","DOIUrl":"https://doi.org/10.1145/1321261.1321275","url":null,"abstract":"A motion trend analysis method is proposed to reconstruct human motion from un-calibrated monocular video. In this paper, relocation of human subject is the main concern, which is one of the most difficult parts in motion reconstruction and critically affects the accuracy of human posture generation. Numerical studies are conducted on experiments from synthetic and real video data to demonstrate the correctness of the recovered human translation in the proposed system.","PeriodicalId":360852,"journal":{"name":"Conference on Computer Graphics and Interactive Techniques in Australasia and Southeast Asia","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128771303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：